Why do I get a Timeout in PortRead() in visual c++? - c++

Question

I am trying jni interfacing for serial port programming, using Microsoft Visual Studio 11 with .NET 4.0.
I get he following error when I try to read from the comm port:
time out happened in PortRead()
The read time out value is set to 5sec.
The following is a part of the code:
Also, since my laptop is 64 bit I'm using a bafo ie a 64 to 32 bit converter, and then attach the rs232 wire.
JNIEXPORT jint JNICALL Java_JavaSerial_Read(JNIEnv *env, jobject obj)
{
jint idata = 0;
char cdata[8];
ERR_CODE rc = OK;
CommPortClass* commClass;
commClass = new CommPortClass;
commClass->iMaxChars = 1;
rc = PortRead(commClass);
if (rc != OK)
Msg("ERROR in PortRead()! ");
sprintf_s(cdata, "%d", commClass->pcBuffer[0]);
idata = atoi(cdata);
delete commClass;
return idata;
}
//Port read function
ERR_CODE PortRead(CommPortClass *hCommPort)
{
HANDLE hThread; // handler for port read thread
DWORD IDThread;
DWORD Ret, ExitCode;
DWORD dTimeout = 5000; // define time out value: 5 sec.
ERR_CODE ecStatus = OK;
if (!(hThread = CreateThread(NULL, 0, (LPTHREAD_START_ROUTINE) ThreadFunc, (LPVOID)hCommPort, CREATE_SUSPENDED, &IDThread) ) )
// no security attributes, use default stack size, parameter to thread function, creation flag - suspended, returns thread ID
{
Msg("Create Read Thread failed");
return EC_CREATE_THREAD;
}
ResumeThread(hThread); // start thread now
Ret = WaitForSingleObject(hThread, dTimeout);
if (Ret == WAIT_OBJECT_0)
{
// Data received & process it... need to do nothing because the data is stored in the
// hCommPort in the Thread Function. The only thing is to close thread handle
CloseHandle(hThread);
}
else if (Ret == WAIT_TIMEOUT) // Time out happened
{
// Warning & kill thread
Ret = GetExitCodeThread(hThread, &ExitCode);
Msg("Time out happened in PortRead() ");
if (ExitCode == STILL_ACTIVE)
{
TerminateThread(hThread, ExitCode);
CloseHandle(hThread);
return EC_RECV_TIMEOUT;
}
else
{
CloseHandle(hThread);
Msg("ERROR in GetExitCodeThread: != STILL_ACTIVE ");
ecStatus = EC_EXIT_CODE;
}
}
else
{
Msg("ERROR in WaitFor SingleObject ");
ecStatus = EC_WAIT_SINGLEOBJ;
}
return ecStatus;
}
//Thread() function
void WINAPI ThreadFunc(void* hCommPorts)
{
char Byte;
BOOL bResult, fDone;
int nTotRead = 0;
DWORD dwCommModemStatus, dwBytesTransferred;
CommPortClass* CommPorts;
ERR_CODE ecStatus = OK;
CommPorts = (CommPortClass* )hCommPorts;
// Specify a set of events to be monitored for the port.
SetCommMask(hPort, EV_RXCHAR | EV_CTS | EV_DSR | EV_RLSD | EV_RING);
fDone = FALSE;
while (!fDone)
{
// Wait for an event to occur for the port.
WaitCommEvent(hPort, &dwCommModemStatus, 0);
// Re-specify the set of events to be monitored for the port.
SetCommMask(hPort, EV_RXCHAR | EV_CTS | EV_DSR |EV_RLSD| EV_RING);
if (dwCommModemStatus & EV_RXCHAR||dwCommModemStatus & EV_RLSD)
{
// received the char_event & loop to wait for the data.
do
{
// Read the data from the serial port.
bResult = ReadFile(hPort, &Byte, 1, &dwBytesTransferred, 0);
if (!bResult)
{
Msg("ERROR in ReadFile !");
fDone = TRUE;
break;
}
else
{
// Display the data read.
if (dwBytesTransferred == 1)
{
CommPorts->pcBuffer[nTotRead] = Byte;
nTotRead++;
if (nTotRead == CommPorts->iMaxChars)
{
fDone = TRUE;
break;
}
}
else
{
if (Byte == 0x0D ||Byte == 0x0A) // null char or CR
{
Msg("Received null character ");
fDone = TRUE;
break;
}
}
}
} while (dwBytesTransferred == 1); //while (nTotRead < pRecv->iMaxChars);
} // if
} // while
return;
}